1. Field of the Invention
The present invention relates to the field of line boring machines for bearing housings in engine heads for the bearings of cam shafts used in the engines.
2. Description of the Prior Art
Various machines have been developed for accurately line boring the housings for bearings that holds rotating shafts in engines, such as cam shafts or crank shafts. In the modern overhead cam engine, the bearings are held in supports or are integral in the engine head, and it is important to be able to properly position the head, hold it securely, do the boring, and then quickly set up for boring the next head. In the prior art, U.S. Pat. No. 2,250,788 issued to Ewald A. Arp on July 29, 1941 shows an early type machine for boring engine bearings. The machine does support an engine block in place on a table for the line boring. U.S. Pat. No. 2,604,284 also shows an adjustable base for a boring machine that is an improvement on U.S. Pat. No. 2,250,788. These machines are not easily adapted for use in boring bearing housings on engine heads, or the like.
U.S. Pat. No. 4,213,721 issued July 22, 1980 and U.S. Pat. No. 4,132,494 issued Jan. 2, 1979, both issued to Aldridge, show modern line boring machines for boring bearing housings in engine blocks using a type of machine that requires relatively elaborate set up, and rigid supports which in turn are quite expensive to make. The device is not easily adapted to boring engine heads.
U.S. Pat. No. 4,168,826 shows an engine block boring stand for boring crank shaft bearings as well as cam shaft bearings, but here too, it is the block being held as opposed to the head, the machine itself is not lightweight, yet rigid and easily made.
Additional patents which illustrate the state of the art include U.S. Pat. Nos. 1,698,862; 2,160,476; 2,170,054; and 2,413,574.
None of these structures show a machine which is the easily contructed, very rigid, and quite easily used with head members for boring the cam bearing bores for upper head cam shaft bearings.